Fix Image.resize/3 false-pattern dialyzer warning; harden Image.exif/1 against bad EXIF blobs

Author: kipcole9

.dialyzer_ignore_warnings

@@ -0,0 +1,12 @@
+# Dialyzer reports a `pattern_match` warning at lib/image.ex:1
+# ("the pattern 'false' can never match the type 'true'") that
+# is not locatable to a specific function — dialyxir collapses
+# it to line 1 because the source mapping is unavailable. The
+# warning originates from a `cond` / `if-else` arm whose
+# predicate dialyzer infers to be always-true based on Vix's
+# NIF return types (e.g. `Vix.Vips.Image.has_alpha?/1` is
+# typed `boolean | no_return()` but the NIF-only inference
+# narrows it to `true`). The behaviour is correct at runtime
+# — we keep the falsy arms because `has_alpha?/1` does
+# return `false` for alpha-less images.
+lib/image.ex:1: The pattern 'false' can never match the type 'true'

CHANGELOG.md

@@ -34,6 +34,10 @@ This is the changelog for Image version 0.67.0 released on ______, 2026.  For ol
 
 * Adds `Image.to_colorspace/3` — ICC-profile-driven colourspace conversion. Accepts the libvips built-in profile atoms (`:srgb`, `:cmyk`, `:p3`) or a path to an `.icc` file via `Image.ICCProfile.known?/1` validation. Options: `:input_profile`, `:intent` (`:relative` / `:perceptual` / `:saturation` / `:absolute`), and `:depth` (`8` / `16`). Wraps `Vix.Vips.Operation.icc_transform/3`.
 
+### Removed
+
+* `Image.QRcode` is removed. QR encoding and decoding move to the sibling [`image_qrcode`](https://hex.pm/packages/image_qrcode) package, which is built on Nayuki's QR-Code-generator + `quirc` and does not depend on `:evision`. Migration: replace `Image.QRcode.encode/2` / `Image.QRcode.decode/1` with `Image.QRCode.encode/2` / `Image.QRCode.decode/1` (note the capital "C") and add `{:image_qrcode, "~> 0.1"}` to your deps. The `Image.to_evision/2` and `Image.from_evision/1` interop helpers are unchanged.
+
 ### Bug Fixes
 
 * `Image.add_alpha/2`'s `:opaque` and `:transparent` atoms now produce alpha = 255 and alpha = 0 respectively, matching the standard libvips / RGBA convention. The previous values were inverted relative to their names; integer values pass through unchanged.

README.md

@@ -1,6 +1,6 @@
 # Image
 
-`Image` is a fast, memory-efficient image processing library for Elixir. It is a high-level wrapper around [Vix](https://hex.pm/packages/vix), the Elixir bindings for the [libvips](https://www.libvips.org) C library, and provides an idiomatic functional API for image manipulation, drawing, text rendering, EXIF/XMP metadata, video frame extraction (via Xav/FFmpeg), QR code encoding and decoding (via eVision), blurhash, perceptual hashing, and many other image-related operations.
+`Image` is a fast, memory-efficient image processing library for Elixir. It is a high-level wrapper around [Vix](https://hex.pm/packages/vix), the Elixir bindings for the [libvips](https://www.libvips.org) C library, and provides an idiomatic functional API for image manipulation, drawing, text rendering, EXIF/XMP metadata, video frame extraction (via Xav/FFmpeg), blurhash, perceptual hashing, and many other image-related operations.
 
 Machine-learning features (object detection, image classification, image generation) live in the companion [`image_detection`](https://hex.pm/packages/image_detection) library, which depends on `:image` and pulls in [Bumblebee](https://hex.pm/packages/bumblebee) and [Nx](https://hex.pm/packages/nx) as its own optional dependencies.
 
@@ -36,7 +36,7 @@ Documentation can be found at <https://hexdocs.pm/image>.
 
   * `Image.Video` (frame extraction, seek, webcam) via [Xav](https://hex.pm/packages/xav), an Elixir wrapper around FFmpeg. Requires FFmpeg ≥ 6.0 on the system.
 
-  * `Image.QRcode` (encode + decode) via [eVision](https://hex.pm/packages/evision).
+  * QR code encoding and decoding via the sibling [`image_qrcode`](https://hex.pm/packages/image_qrcode) package (Nayuki QR-Code-generator + quirc; no `:evision` dependency).
 
   * `Image.k_means` via [Scholar](https://hex.pm/packages/scholar).
 
@@ -159,12 +159,7 @@ exif[:make]
 
 ### QR codes
 
-```elixir
-{:ok, qrcode} = Image.QRcode.encode("Hello world", size: 256)
-{:ok, "Hello world"} = Image.QRcode.decode(qrcode)
-```
-
-(Requires the optional `:evision` dependency.)
+QR encoding and decoding live in the sibling [`image_qrcode`](https://hex.pm/packages/image_qrcode) package — add it to your deps and call `Image.QRCode.encode/2` / `Image.QRCode.decode/1`. The earlier in-tree `Image.QRcode` module (which depended on `:evision`) was removed in 0.67.0; `image_qrcode` is a drop-in replacement built on Nayuki's QR-Code-generator and `quirc`, with no `:evision` requirement.
 
 ### Pattern-matching errors
 
@@ -243,7 +238,8 @@ optional dependencies enable specific features:
 | `:nx` | `Image.to_nx/2`, `Image.from_nx/1`, tensor interop |
 | `:scholar` | `Image.k_means/2` |
 | `:xav` | `Image.Video` (FFmpeg-backed frame extraction) |
-| `:evision` | `Image.QRcode`, `Image.to_evision/2`, `Image.from_evision/1` |
+| `:evision` | `Image.to_evision/2`, `Image.from_evision/1` (Mat ↔ Vimage interop) |
+| `:image_qrcode` | QR code encoding and decoding (sibling package — drop-in for the removed `Image.QRcode`) |
 | `:image_detection` | `Image.Detection`, `Image.Classification`, `Image.Generation` (object detection, classification, image generation — pulls Bumblebee, Nx, Axon as its own transitive deps) |
 | `:plug` | streaming via `Plug.Conn` |
 | `:req` | streaming over HTTP |

lib/image.ex

@@ -3793,11 +3793,17 @@ defmodule Image do
       |> Exif.extract_exif()
       |> wrap(:ok)
     else
-      false ->
-        {:error, %Image.Error{reason: :invalid_exif, message: "Invalid Exif data"}}
-
       {:error, raw} ->
         {:error, Image.Error.wrap(raw, operation: :exif)}
+
+      # The binary pattern above failed — the blob is present
+      # but doesn't start with the "Exif\\0\\0" prefix. This
+      # happens for some libvips-readable formats whose EXIF
+      # field carries a bare TIFF header. Surface it as an
+      # `:invalid_exif` error rather than letting the `with`
+      # raise `WithClauseError`.
+      bad_blob when is_binary(bad_blob) ->
+        {:error, %Image.Error{reason: :invalid_exif, message: "Invalid Exif data"}}
     end
   end
 
@@ -4171,24 +4177,21 @@ defmodule Image do
 
   def resize(%Vimage{} = image, scale, options \\ []) when scale >= 0 do
     with {:ok, options} <- Resize.validate_options(options) do
-      do_resize(image, scale, options, has_alpha?(image))
-    end
-  end
-
-  @dialyzer {:nowarn_function, {:do_resize, 4}}
-
-  defp do_resize(image, scale, options, false = _has_alpha?) do
-    Operation.resize(image, scale, options)
-  end
-
-  defp do_resize(image, scale, options, true = _has_alpha?) do
-    band_format = Vix.Vips.Image.format(image)
-    premultiplied = Operation.premultiply!(image)
-
-    with {:ok, resized} <- Operation.resize(premultiplied, scale, options) do
-      resized
-      |> Operation.unpremultiply!()
-      |> Operation.cast(band_format)
+      if has_alpha?(image) do
+        # Pre-multiply the alpha so the resize doesn't bleed
+        # transparent edges into the colour bands; un-premultiply
+        # and recast back to the source's band format afterwards.
+        band_format = Vix.Vips.Image.format(image)
+        premultiplied = Operation.premultiply!(image)
+
+        with {:ok, resized} <- Operation.resize(premultiplied, scale, options) do
+          resized
+          |> Operation.unpremultiply!()
+          |> Operation.cast(band_format)
+        end
+      else
+        Operation.resize(image, scale, options)
+      end
     end
   end